Tongue jack

ABSTRACT

A tongue jack includes a vertical channel member having a rack positioned in a longitudinal slot of the channel member. A caster wheel is attached at one end of the channel member. A housing which may be mounted on a tongue includes a drive gear and a pinion. The housing wraps around the channel member so that the pinion may translate the housing relative to the channel member and thereby elevate or lower the tongue.

United States Patent Brockelsby et al.

[451 Nov. 25, 1975 TONGUE JACK Inventors: Norman D. Brockelsby, Grand Island; Reinhold A. Haase, Hastings,

both of Nebr.

Assignee: Dutton-Lainson Company, Hastings,

Nebr.

Filed: Mar. 24, 1975 Appl. No.: 561,154

U.S. Cl. 254/86 R; 254/97 Int. Cl. B608 9/02; B66F 3/16 Field of Search 254/45, 95-97,

References Cited UNITED STATES PATENTS Ackerman 254/97 Griffis 254/86 R Hewes, Jr. et al. 254/97 3,l36,527 3,466,0ll

Primary Examiner-Othell M. Simpson Attorney, Agent, or Firm-Molinare, Allegretti, Newitt & Witcoff [57] ABSTRACT A tongue jack includes a vertical channel member having a rack positioned in a longitudinal slot of the channel member. A caster wheel is attached at one end of the channel member. A housingwhich may be mounted on a tongue includes a drive gear and a pinion. The housing wraps around the channel member so that the pinion may translate the housing relative to the channel member and thereby elevate or lower the tongue.

13 Claims, 5 Drawing Figures ,1 U.S Patent N0v.25, 1975 Sheet10f2 3,921,958

U.S Patent Nov. 25, 1975 Sheet20f2 3,921,958

74 FIG.3

TONGUE JACK BACKGROUND OF THE INVENTION In a principal aspect, the present invention relates to a jack and more particularly to a tongue jack of the type used in combination with boat trailers and the like.

It is common to attach a jack mechanism to the forward tongue of a boat trailer so that when the trailer is not attached to a pull hitch, it can be maintained at an appropriate elevation for storage and subsequent attachment to a hitch. Preferably, such jacks are adjustable in height and are capable of assuming a non-interferring position once the tongue is attached to an appropriate pull hitch. Generally, such jacks are not themselves subjected to heavy loads.

Prior art jacks were usually constructed by providing a cylindrical post with a rack riveted to the outside of the post. A pinion mounted in a housing is then driven by a crank handle against the rack. The housing is attached to the tongue of the trailer. Operating the pinion against the rack moves the housing (tongue) relative to the post.

This prior art structure works adequately. However, the rack, since it is mounted on the external portion of the post, can be hazardous. Moreover, the rack must be lubricated. It, therefore, provides a source of soil. Finally, the exposed teeth on the rack are likely to be damaged, thus rendering the jack inoperative. It is problems of this nature which the subject matter of the present invention seeks to overcome.

SUMMARY OF THE INVENTION In a principal aspect, the present invention is an improved jack comprising a post having a rack positioned in a vertical slot in the post. The rack is thus recessed and cooperative with a pinion mounted in a housing assembly. The housing assembly is slidably mounted on the post and moves in response to operation of the pinion by driving means.

It is thus an object of the present invention to provide an improved jack and, in particular, an improved tongue jack which has fewer pinch points for increased operator safety.

It is a further object of the present invention to provide an improved jack construction of the type including a post with a recessed rack, the post having a caster wheel at one end thereof.

Still another object of the present invention is to provide an improved jack construction wherein a caster wheel assembly is included, the caster wheel being lockable in a fixed position whenever the jack is not in use.

Another object of the present invention is to provide an improved jack, particularly for use in cooperation with a tongue of a trailer or the like, the jack being of inexpensive reliable construction.

These and other objects, advantages and features of the invention will be set forth in the detailed description which follows.

BRIEF DESCRIPTION OF THE DRAWING In the detailed description which follows, reference will be made to the drawing comprised of the following figures:

FIG. 1 is a perspective view illustrating the improved jack of the present invention attached to a trailer tongue;

FIG. 2 is an enlarged perspective view partially cut away and further illustrating the jack of the present invention;

FIG. 3 is a side elevation of the jack of the present invention;

FIG. 4 is a section through the jack taken along the lines 44 in FIG. 3; and

FIG. 5 is a rear elevation illustrating the caster wheel locking mechanism.

DESCRIPTION OF THE PREFERRED EMBODIMENT The jack of the present invention is particularly designed for use as a tongue jack. That is, the jack is designed for attachment to the tongue of a trailer, although it has other possible applications including use as a leveling jack for camper trailers and the like or as a lifting jack for light industrial equipment. The jack thus provides a large range of vertical travel associated with improved safety and reliability.

Referring to FIG. 1, jack 10 is attached to a tongue 12 associated with a trailer. The jack 10 includes a post assembly 14 housing 16 and a caster wheel assembly 18. The housing 16 is attached by means of a mounting bracket to the top surface of tongue 12. Operation of a handle 20 causes the post assembly 14 and the caster wheel assembly 18 to be raised or lowered relative to tongue 12 in response to clockwise or counterclockwise rotation of the handle 20. A power drive, such as a motor may be substituted in place of the manual crank handle 20.

Referring to the additional figures, the specific structural details of the jack are illustrated. The post assembly 14 is comprised of a single sheet of rolled steel which has been formed by means of a cold rolling operation into a substantially rectangular cross section post 22. That is, the post 22 was originally a flat strip. The strip is formed into a substantially square member having first, second and third longitudinal channels 23-25 formed intermediate adjacent corners 27-30. The fourth side of the post 22 is comprised of the inwardly folded ends 32 and 34 of the sheet stock. These inwardly folded ends 32, 34 define a slot 36.

A rack 38 formed from first and second parallel plates 40 and 42 is inserted in slot 36. It is important that the rack 38 be retained completely within the slot 36 so that teeth 44 of rack 38 do not project beyond corners 27 and 30. Preferably, the plates 40 and 42 defining the rack 38 extend from the front edge of slot 36 to the backside of channel 24. This improves the structural integrity of the post assembly. The rack 38 also extends from substantially the top of the post 22 to the bottom thereof. Stop members as at 46 may be incorporated at one or both ends of the rack to limit the travel of a cooperating pinion 48 in housing 16.

The housing 16 is comprised of first and second shell members 50 and 52. Spaced rodsor pins 54 cooperatively engage opposite walls 56 and 58 of members 50 and 52 and hold the housing 16 together. Rivets 60 engage overlapping ends 62 and 64 of members 50 and 52. Note that the head of the rivet 60 fits within chanhe] 24 and that the portions of end 62 on either side of the head of the rivet 60 act as bearing surfaces for the longitudinal corners 28 and 29. The housing 16 includes outwardly extending flanges 86 and 88 which cooperate with plates as at 90 and bolt as at 92 in FIG. 1 to attach the housing 16 to the tongue 12.

Thus. the housing 16 is attached to the top surface of the tongue 12 in order that the post 22 may be in opposed relation with the next adjacent or side surface of the tongue 12. In this manner, the rack 38 is positioned in protected close relation to the tongue 12 and thelongitudinal axis of the post 22 is almost coincident with the longitudinal axis of the tongue 12. This improves the stability of the tongue jack and insures that the rack 38 will he in a nearly unexposed position.

Pinion 48 is mounted on a shaft 66 fixed in bushings 68 and 70 in members 50 and 52 respectively. Teeth 72 of pinion 48 mesh with teeth 44 of rack 38. A drive shaft 74 is attached to a worm gear 76 and is mounted in bearings 78 and 80 fixed respectively in end wall 82 and bracket 84 suspended between walls 56 and 58. Handle is keyed to shaft 74. Rotation of the handle 20 causes worm gear 76 to drive pinion 48 along rack 38.

A protective cap 94 may be positioned on the top end of the post 22. The caster wheel assembly 18 is slidably inserted at the opposite end of the post 22. Caster wheel 18 includes a bracket 96 with an axle 98 upon which wheel 100 is mounted. The bracket 96 is inserted in the post 22 to provide a swivel mount. Preferably, the axis of axle 98 is offset to one side of the longitudinal axis of post 22 to improve the trailing characteristics of the jack.

As illustrated in FIG. 5, the caster wheel assembly 18 and in particular the bracket 96 includes a tab projection 102 cooperative with a detent or notch 104 defined in the ends 62 and 64. Thus, when the post 22 is raised to an elevated position, it is possible to lock the caster wheel assembly 18 in a fixed position to thereby prevent undesired movement of that wheel assembly. Thus. projection 102 fits within notch 104 as suggested in FIG. 5.

While in the foregoing, there has been set forth a preferred embodiment of the present invention, it is to be understood that the invention shall be limited only by the following claims and their equivalents.

What is claimed is:

1. An improved jack comprising, in combination:

a post assembly including a post, said post including a vertical slot with a rack therein having outwardly extending teeth retained in said slot; and

a housing assembly slidably mounted on said post,

said housing assembly including a pinion cooperative with said rack; and

means for driving said pinion and translating said housing relative to the post assembly.

2. The improved jack of claim 1 wherein said post defines .a substantially rectangular cross section wherein said rack is retained within the area of that cross sec tion.

3. The improved jack of claim 1 wherein said post is comprised of a substantially rectangular channel memher and wherein said rack is defined by at least one plate member retained within a longitudinal slot in said channel member.

4. The improved jack of claim 1 wherein said housing includes gear means for driving said pinion said gear means providing a mechanical advantage for the means for driving.

5. The improved jack of claim 1 wherein said means for driving includes a crank drivingly connected with said pinion.

6. The improved jack of claim 1 wherein said post assembly includes a caster wheel attached at one end.

7. The improved jack of claim 1 wherein said rack includes a stop member for cooperation with said pinion at one end of said rack.

8. The improved jack of claim 1 wherein said post includes a caster wheel at one end and wherein said wheel and housing include cooperative means which engage and prevent rotation of said caster wheel upon movement of said post with respect to said housing to an end position.

9. The improved jack of claim 1 in combination with a tongue member.

10. The improvedjack of claim 9 wherein said rack is directly opposed to one side of said tongue member, said housing being mounted on the next adjacent side of said tongue member.

11. The improved jack of claim 1 includinga caster wheel at one end of said post, said caster wheel having a rotation axis offset from the longitudinal axis of said post.

12. The improved jack of claim 1 including a worm gear cooperative with said pinion, said pinion being rotatable about an axis perpendicular to the direction of travel of said housing relative to said post, said worm gear being rotatable about another axis perpendicular to the axis of said pinion.

13. The improved jack of claim 1 wherein said housing assembly is comprised of a plate member extending around said post in the form of a clamp wherein the side of the post opposite the rack constitutes a bearing surface cooperative with said plate member. 

1. An improved jack comprising, in combination: a post assembly including a post, said post including a vertical slot with a rack therein having outwardly extending teeth retained in said slot; and a housing assembly slidably mounted on said post, said housing assembly including a pinion cooperative with said rack; and means for driving said pinion and translating said housing relative to the post assembly.
 2. The improved jack of claim 1 wherein said post defines a substantially rectangular cross section wherein said rack is retained within the area of that cross section.
 3. The improved jack of claim 1 wherein said post is comprised of a substantially rectangular channel member and wherein said rack is defined by at least one plate member retained within a longitudinal slot in said channel member.
 4. The improved jack of claim 1 wherein said housing includes gear means for driving said pinion said gear means providing a mechanical advantage for the means for driving.
 5. The improved jack of claim 1 wherein said means for driving includes a crank drivingly connected with said pinion.
 6. The improved jack of claim 1 wherein said post assembly includes a caster wheel attached at one end.
 7. The improved jack of claim 1 wherein said rack includes a stop member for cooperation with said pinion at one end of said rack.
 8. The improved jack of claim 1 wherein said post includes a caster wheel at one end and wherein said wheel and housing include cooperative means which engage and prevent rotation of said caster wheel upon movement of said post with respect to said housing to an end position.
 9. The improved jack of claim 1 in combination with a tongue member.
 10. The improved jack of claim 9 wherein said rack is directly opposed to one side of said tongue member, said housing being mounted on the next adjacent side of said tongue member.
 11. The improved jack of claim 1 including a caster wheel at one end of said post, said caster wheel having a rotation axis offset from the longitudinal axis of said post.
 12. The improved jack of claim 1 including a worm gear cooperative with said pinion, said pinion being rotatable about an axis perpendicular to the direction of travel of said housing relative to said post, said worm gear being rotatable about another axis perpendicular to the axis of said pinion.
 13. The improved jack of claim 1 wherein said housing assembly is comprised of a plate member extending around said post in the form of a clamp wherein the side of the post oppoSite the rack constitutes a bearing surface cooperative with said plate member. 